Locking device for sectional conduits.



I. STEARNS.

LOCKING DEVICE FOR sEcTloNAL coNnulTs.

APPLICATION FILED APR-18 1912.

Mx/Jaw ISAAC STEARNS, 0F DETROIT, MICHIGAN, ASSIGNOR TO MICHIGAN SAFETY FURNACE PIPE COMPANY, 0F DETROIT, MICHIGAN, A CORPORATION 0F MICHIGAN.

LOCKING DEVICE FR SECTIONAL CONDUITS.

lll 52,56%

Speccation of Letters Patent.

Patented Sept. t, I9I5.

Application flled April 18, 1912. Serial No. 691,639.

To all whom t may concern.'

Be it known that I, ISAAC STEARNS, a citizen of the United States of America, residing at Detroit, in the county of IVayne`v and State of Michigan, have invented certain new and useful Improvements in Locking Devices for Sectional Conduite, of which the following is a specification, reference being had therein to the accompanying drawings.

The invention relates to sectional conduits and more particularlyto that type employed for'hot air conductors for furnaces, and it is the object of the invention to provide means for locking the adjacent sections to each other.

To this end the invention consists in the construction as hereinafter set forth.

In the drawings,-Figure 1 is a side elevation of the ends of adjacent conduit sections in position for lengagement with each other; Fig. 2 is a cross section showing said ends in engagement and locked.; Fig. 3 isa sectional perspective view of the parts in the position shown in Fig. 1. y

In the construction of sectional conduits employed for hot air conductors one type which has gone into extensive use is known as the safety pipe and is provided with spaced outer and inner walls. The joint between adjacent sections is formed by od'- setting the ends of these outer and inner walls and oppositely at the two ends of the section so that when telescoped a double brake joint is formed. As shown, A-is the inner wall of the section and B the spaced outer wall thereof. is a spacer for sepa# rating the walls A and B which has a portion D parallel to the inner wall terminating in the return-bent Hange Fi over the end of said wall, and a portion F parallel to the outer wall and return bent at G over the end thereof. At the opposite end of the section the spacer I-I is preferably formed integral with the inner wall and has the portion I parallel with the outer wall and connected thereto by the return bent flangel J. Thus when the two ends of adjacent sections are engaged with each other a double brake telescopic joint will be formed.

. To lock the 4sections when engaged from accidental disengagement I preferably provide a laterally bent tongue upon the one for" engaging a registering slot or recess on the other. As shown, the flange I has a p0rtion K thereof which is separated from the body portion by slits L. The outer end of this portion K is then bent outward at M and forms the locking tongue or hook M which is engageable with a slot N in the flange F of the adjacent parallel outer wall of the section. Thus when the two inter-- engageable ends of the adjacent sections are telescoped the tongue M will first be sprung inward and then as it comes into registration with the slot N will be forced outward, forming a locking engagement. This will hold the sections from becoming detached,

but at any time that it is necessary to detach them a slight pressure on the wall of the tongue section will disengage the hook from the slot and permit detachment.

What I claim as my invention is:

1. The combination of telescoping conduit sections each being provided with paral lel outer and inner walls, and each having a spacer between said walls and having a portion lying adjacent to the outer wall to form a double ply flange, and the doubleply Harige of one of the sections having a tongue formed out of a portion thereof, said tongue being separated from the remaining portion of said double-ply flange byslits and having its outer end 'laterally bent to form a hook, the other section being provided with a slot in the telescoping flange for engagement with said laterally bent hook.

2. The combination with telescopically engaging conduit sections having parallel inner and outer walls, of a spacer extending between the walls of each of said sections and provided with an outward extension parallel and adjacent to the outer wall to form a two-ply flange, the flange of one sec tion having a tongue formed therefrom, said tongue being separated the remaining In testimony whereof I affixY my signature portion of the last-mentioned Bange by lonf in presence of two witnesses. gitudinal slits and being laterally bent to form e hook, the telescoping liange ofthe ISAAC STEARNS' 5 adjacent section being `slotted. to form a Witnesses: keeper -for engagement with said laterally JAMES P. BARRY,

bent hook. y l CHARLES B. BELKNAP. 

